U.S. patent number 4,931,908 [Application Number 07/325,631] was granted by the patent office on 1990-06-05 for housing for an electronic circuit.
This patent grant is currently assigned to Siemens Aktiengesellschaft. Invention is credited to Michel R. J. Boucard, Thirion C. Francois.
United States Patent |
4,931,908 |
Boucard , et al. |
June 5, 1990 |
Housing for an electronic circuit
Abstract
The housing comprises a bottom 1 in the thickness of which the
extension of an input/output pin 5 of the housing is embedded. This
extension ends in a contact terminal 15 which lies flush with the
surface of a substrate 7 carrying passive or active electronic
components 11, 12 and interconnecting conductor tracks 10, 10',
10". A conductor track 10 passing over an opening 6 in the
substrate which accommodates the terminal 15 is soldered onto this
terminal in order to interconnect a terminal 14 of the component 12
with the input/output pin 5 of the housing. An interconnection via
side terminals 13, 13', 13", . . . , which complicates the layout
of the conductor tracks to be provided for this purpose, is thus no
longer required.
Inventors: |
Boucard; Michel R. J.
(Tournefeuille, FR), Francois; Thirion C. (Auterive,
FR) |
Assignee: |
Siemens Aktiengesellschaft
(Munich, DE)
|
Family
ID: |
9364801 |
Appl.
No.: |
07/325,631 |
Filed: |
March 20, 1989 |
Foreign Application Priority Data
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Mar 30, 1988 [FR] |
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88 04199 |
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Current U.S.
Class: |
361/743;
257/E23.174; 361/761; 361/774; 361/792 |
Current CPC
Class: |
H01L
23/5384 (20130101); H05K 3/4084 (20130101); H01L
24/24 (20130101); H05K 3/202 (20130101); H05K
3/32 (20130101); H05K 3/4092 (20130101); H05K
2201/0382 (20130101); H05K 2201/0391 (20130101); H05K
2201/0394 (20130101); H05K 2201/0397 (20130101); H05K
2201/09118 (20130101); H05K 2203/063 (20130101); H05K
2203/1461 (20130101); H01L 2224/48091 (20130101); H01L
2924/19107 (20130101); H01L 2224/48091 (20130101); H01L
2924/00014 (20130101); H01L 2924/14 (20130101) |
Current International
Class: |
H01L
23/538 (20060101); H01L 23/52 (20060101); H05K
7/20 (20060101); H05K 3/40 (20060101); H05K
3/20 (20060101); H05K 3/32 (20060101); H05K
001/14 () |
Field of
Search: |
;174/68.5
;361/395,397,399,400,401,46X,48X,409,412,414X |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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2603763 |
|
Mar 1988 |
|
FR |
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2136203 |
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Sep 1984 |
|
GB |
|
Other References
Landis, "High-Speed Packaging For GaAs Interconnection", 3/85, pp.
384-388..
|
Primary Examiner: Thompson; Gregory D.
Attorney, Agent or Firm: Wells; Russel C. Boller; George
L.
Claims
We claim:
1. Housing for an electronic circuit, comprising a bottom onto
which is fixed a substrate made of insulating material, at least
one surface of which carries active and/or passive components and
electrical conductor tracks or bands connecting the components to
one another, and/or electrical contact pins emerging outside the
housing so as to ensure interconnection of the circuit contained
inside the housing with at least one electrical and/or electronic
apparatus associated with and located outside the housing,
characterized in that at least one (5) of the pins extends inside
the thickness of the wall of the bottom (1) of the housing so as to
pass through the surface of the bottom of the housing which
supports the substrate and pass into an opening (6) formed in the
substrate so as to present one end in the form of a contact
terminal (15) which lies flush with the surface of the substrate
carrying the conductor tracks or bands, at least one (10) of these
tracks or bands passing above this opening in such a way as to be
in electrical contact with this contact terminal of the pin.
2. Housing according to claim 1, characterized in that it comprises
several pins, the ends of which outside the housing are aligned
while the contact terminals of these pins which lie flush with the
substrate surface carrying conductor tracks are dispersed over this
surface.
3. Housing according to claim 1, characterized in that the
substrate made of insulating material is metallized on its two
surfaces in accordance with conductor track or band configurations,
the contact terminal lying flush with a pin passing through both
the metallized surface of the substrate which is in contact with
the bottom of the housing and the thickness of the substrate, in
order to come into electrical contact with at least one track or
band on the other surface of the substrate.
4. Housing according to claim 1, characterized in that the
substrate comprises several metal layers separated from each other
in its thickness, the contact terminal of a pin coming into
electrical contact with one of the external layers and the
electrical connection between these layers being effected via
metallized holes formed in these layers and in the substrate.
5. Housing according to claim 1, characterized in that the
substrate is covered on its two surfaces by metal layers
interconnected by lugs according to the interconnection method
called "dual layer TAB".
6. Housing according to claim 1, characterized in that the
conductor track or band is soldered onto the contact terminal of
the pin.
Description
FIELD OF INVENTION
The present invention relates to a housing for an electronic
circuit and, more particularly, to such a housing designed to
protect an electronic circuit with automatable connections.
An electronic circuit consisting of several active or passive
components arranged on a substrate is commonly arranged inside a
housing which protects it from external attack. It is therefore
necessary to effect electrical connections between the circuit
located inside the housing and an electrical and/or electronic
environment outside this housing so that the various input or
output signals necessary for the housing to operate in this
environment can be transmitted. By way of an example of such a
situation, mention may be made of the case where an electronic
circuit housing, by processing suitable signals, operates various
actuators on the basis of signals received from various sensors.
Such a situation is frequently found in automotive-car
electronics.
Conventionally, the necessary electrical connections are
established by means of pins which pass through the wall of the
housing and which are arranged in lines so as to be able to
cooperate with a multipole connector suitable for connecting each
pin to a source of a circuit input signal or to a component or
apparatus using the signal processed by the circuit. Inside the
housing, the connection between these pins and the circuit is
effected by metal strips or wires, each soldered at one end onto a
pin and, at the other end, onto a metal contact terminal forming
part of a series of terminals arranged in line parallel to one of
the edges of the substrate on which the electronic circuit is
mounted. The presence of two soldering zones for each connection
may thus be noted. Reducing the number of these soldering points in
order to increase the reliability of the circuit and reduce its
manufacturing cost has been contemplated. To achieve this, it has
been proposed that the housing be equipped with a pin which is
extended, inside the housing, by a flexible lug formed as one piece
with the pin, the single free end of this lug being then soldered
onto a contact terminal located close to one edge of the circuit
substrate.
In addition to the cited drawbacks of the wire or metal strip
connections with two soldered end zones, it will be noted that all
the connection methods described above, which form part of the
prior art, have the drawback that the connection terminals mounted
on the substrate must be aligned in a zone close to at least one
edge of the substrate, itself parallel to a series of pins passing
through the housing, be it merely in order to reduce the length of
the connecting strips or wires. Various conductor tracks, mounted
on the substrate, connect the terminals of the substrate to the
actual electronic circuit. It is obvious that these tracks must
avoid each other, thereby complicating the layout of the tracks
mounted on the substrate.
The object of the present invention is to provide a housing for an
electronic circuit which is designed to simplify the electrical
connections effected between this circuit and input/output pins of
the housing and which does not require that these connections be
established by means of specialized contact terminals arranged in
the vicinity of at least one of the edges of a substrate on which
the electronic circuit is mounted.
Another object of the present invention is to provide such a
housing in which the electrical connections make use of conductor
tracks normally arranged on the circuit substrate.
Yet another object of the present invention is to provide such a
housing designed so as to impose no topographical constraints as
regards the location of the electrical connections between the
circuit and the input/output pins of the housing, such that there
is therefore great flexibility with regard to installation of these
connections.
A further object of the present invention is to provide a housing
for an electronic circuit suitable for the electrical connections
to be effected in an automated manner during the mass-production of
such a housing.
These objects of the invention, as well as others which will become
apparent in the remainder of the present description, are achieved
with a housing for an electronic circuit comprising a bottom onto
which is fixed a substrate made of insulating material, at least
one surface of which carries active and/or passive components and
electrical conductor tracks or bands connecting the components to
one another and/or to electrical contact pins emerging outside the
housing so as to ensure interconnection of the circuit contained
inside the housing with at least one electrical and/or electronic
apparatus associated with and located outside the housing,
characterized in that at least one of the pins extends inside the
thickness of the housing wall so as to pass through the surface of
the bottom of the latter which supports the substrate and pass into
an opening formed in the latter so as to present one end flush with
the surface of the substrate carrying the conductor tracks or
bands, at least one of these tracks or bands passing above this
opening in such a way as to be in electrical contact with this end
of the pin.
Thus, as a result of the housing according to the invention, it is
no longer necessary to form, on the substrate, conductor tracks
which could hinder the connection of a particular track to an input
or output pin, by means of a connection terminal formed in the
proximity of one edge of the substrate. It is therefore possible to
free this substrate from the tracks conventionally used to connect
the circuit to the pins.
The housing according to the invention also results in a greater
flexibility in the choice of connection points between the pins and
the circuit since the said pins may be located on any point of the
substrate, thereby helping optimize the layout of the circuit
mounted on the substrate owing to the additional freedom which is
thus offered to the circuit designer.
DESCRIPTION OF THE DRAWINGS
In the accompanying drawings:
FIG. 1 is a partial perspective and sectional view of a housing for
an electronic circuit according to the present invention,
FIG. 2 is a sectional view of a part of a housing according to a
second embodiment of the invention,
FIG. 3 is a sectional view of a part of a housing according to a
third embodiment of the invention, and
FIG. 4 is a sectional view of a part of a housing according to a
fourth embodiment of the invention.
DETAILED DESCRIPTION
Reference is made first of all to FIG. 1 which shows a part of the
bottom 1 of the housing according to the invention, defined by two
mutually perpendicular cutting planes. The same numerical
reference, indexed where necessary, indicates in the Figures
elements or members which are identical or similar.
The housing is closed hermetically by a cover (not shown) fixed
onto an upper opening of the bottom. From a side wall 3 of the
bottom 1 there emerges a seating 4 designed to protect groups of
electrical connection pins 5, 5', etc. arranged for example in two
parallel lines. This seating is dimensioned so as to receive in
complementary fashion a connector (not shown) which establishes a
connection between an electronic circuit contained inside the
housing and external members or apparatus which exchange electrical
signals with the circuit which the housing has the function of
protecting from possible deterioration resulting from external
factors (humidity, temperature, dust, etc.). Holes are formed in an
extension (not shown) of the bottom of the housing. These holes are
intended to have fixing members such as screws passing through
them, for fixing the housing on a support in the position for use.
All these arrangements are commonly used and will not be described
further.
Conventionally still, a substrate 7 suitable for receiving
components of the electrical circuit is fixed onto the bottom of
the housing. This bottom may be made of an organic or inorganic
material and have a multilayered structure with conduction layers
as will be seen below, and conductor tracks such as 10, 10', 10"
(see FIG. 1), as is well known. The substrate may consist of a
polyimide, epoxy resin or ceramic sheet, for example, possessing
thicknesses of between 0.1 and 1 mm, this sheet having conductor
tracks.
Passive or active components of all types are mounted on the
substrate according to the particular organization of the circuit,
these components being intended to make the latter perform certain
functions. The passive components may be resistors, capacitors or
self-induction coils which are conventional or of the
surface-mounted type for example. The active components may consist
of discrete or integrated components in the form of a chip which is
exposed or inside a casing of various known types. By way of
example, FIG. 1 shows, on the circuit substrate contained inside
the housing, a surface-mounted resistor 8 and an encased integrated
circuit 9 for surface mounting. The circuit may also comprise other
components 11, 12. By way of example, the component 11 may be an
integrated circuit having several output terminals. In FIG. 1 it
can be seen that the conductor tracks 10', 10" connect one of these
output terminals to a pin 5' of the housing according to the
invention, so as to allow the integrated circuit 11 to exchange
signals with electrical or electronic apparatus outside the
housing, via the pin 5'. In FIG. 1 it can be seen that, owing to
the proximity of the integrated circuit 11 in relation to the edge
of the substrate which is parallel to the wall 3 of the housing
which carries the input/output pins, it is possible to connect in a
simple manner the circuit 11 to the pin 5' by means of conductor
tracks running along the upper surface of the substrate 7.
Conventionally, this connection is completed by a conduction wire
soldered at its ends, on the one hand, to the pin 5' and, on the
other hand, to a contact terminal 13. In the drawing it can be seen
that this contact terminal 13 forms part of a set of terminals 13,
13', 13", etc. formed parallel to the edge of the substrate which
is located opposite the wall 3 of the housing which carries the
pins, as is conventional.
Reference is now made to the component 12 shown in FIG. 1 as
occupying, in relation to the set of terminals 13, 13', 13", a
position further removed than that occupied by the integrated
circuit 11. The component 12 is itself, for example, an exposed
integrated circuit comprising several output terminals, one of
which is conventionally connected by a wire soldered to a contact
terminal 14 formed on the substrate. Owing to the intermediate
positions occupied by the conductor tracks 10' and 10" on the
substrate, it will be easily understood from an examination of FIG.
1 that it is difficult, or even impossible, to connect the terminal
14 to the pin 5 for example, by means of a conductor track running
along the substrate 7. In order to overcome this difficulty, the
conventional solution consists in complicating the configuration of
the tracks 10' and 10" so as to clear a path towards a contact
terminal of the series 13, 13', 13" etc., for a conductor track
which starts from the terminal 14. Such complications hinder the
design of the conductor tracks to be formed on the substrate 7.
According to the present invention, this difficulty is eliminated
by suitably extending the pin 5 inside the thickness of the wall of
the housing in such a way that one end of this pin is able to lie
flush, through an opening formed in the substrate, with the surface
of this substrate which carries the conductor tracks, in a position
where the connection of this pin to the terminal 14, for example,
may be effected simply by a conductor track 10 running inside a
space formed on the substrate surface as far as the contact
terminal 14. To achieve this, the pin 5 is profiled so as to
correspond the substrate. Such arrangements where tracks pass over
the openings may be obtained by the conventional "subtractive"
method used to form printed circuits. According to this method,
firstly the openings for the terminals to pass through are formed
in the substrate, the substrate is then laminated with a layer of
copper, with or without glue. In order to apply the invention, a
copper sheet with a thickness of 35 or 70 micrometres will
preferably be used. The copper sheet is then covered with a dry
photosensitive film, on the substrate side, the other side of the
copper sheet is doubled by lamination with a reinforcing film which
covers at least the entire surface of the opening. After exposure
of the photosensitive film to the track configuration required for
the substrate and removal of this film, a track portion is
obtained, passing above the opening from one edge to the other of
the latter. Other known methods could be used for this purpose. By
way of example, mention may be made of the interconnection method
known as TAB (from the English expression "Tape Automated Bonding")
in its version called "dual layer TAB".
Of course, the openings in the pin/circuit connection zones of the
substrate could be entirely closed by a conduction band and not
merely partially covered by a conductor track such as those
referred to above.
The housing according to the invention could preferably be made
using the injection-moulding method. More precisely, the pins such
as the pin 5 are therefore fixed against the bottom of a mould by
means of holding studs, in predetermined positions corresponding to
those assigned to the terminal 15 on the bottom of the housing to
be obtained, and the method of double moulding is then used in
order to fix the pins in position and then fill the locations
occupied by the holding studs, after withdrawal of the latter.
Various thermoplastic or thermosetting materials may be used for
the injection operations, as chosen by the person skilled in the
art. It is possible, for to the shape of the walls of the housing
inside which it must pass in order to reach an opening 6 in the
substrate. In the region of this opening 6, the pin 5 is folded
again in such a way that its end assumes the shape of a terminal 15
lying flush with the surface of the substrate 7. This terminal 15
could also be mounted by means of riveting or soldering. According
to the invention, the track 10 passes above the opening 6 in such a
way as to come into contact with the terminal 15. The electrical
contact between the terminal 15 and the track 10 is effected by a
suitable solder joint obtained using conventional methods,
electrical soldering, metal remelting, thermocompression, etc. Of
course, the conductor track 10 and the terminal 15 of the pin 5 are
made of materials which enable the chosen soldering method to be
used.
It will be understood that, owing to the particular configuration
of the pin 5 incorporated in the housing according to the
invention, it is possible to have a connection terminal such as 15
emerging over most of the surface of the substrate, which means
that one is not limited, as regards the connections with the pins
of the housing, to the terminals 13, 13', 13" etc. aligned along
one edge of the substrate. Thus, the geometrical projection of the
pin on the surface of the substrate which supports conductor tracks
may intersect at least one of these conductor tracks. The
distribution of the contact terminals 15 and openings 6 associated
with these terminals, over the surface of the substrate may
therefore be balanced and allow the occupation of areas of this
substrate which otherwise would remain unoccupied. It is therefore
possible to free the surface of the substrate from conductor tracks
such as 10', 10" which serve solely to establish, on one edge of
the substrate, connections between terminals or pins of electronic
components and input/output pins of the housing.
The substrate located inside the housing according to the invention
must comprise portions of conductor tracks which pass above
openings such as the opening 6 in example, to choose the products
sold under the names RYTON, VALOX 420, RINITE 530, which are
marketed by the companies called PHILLIPS PETROLEUM, GENERAL
ELECTRIC and DU PONT DE NEMOURS, respectively.
Reference is now made to FIGS. 2 to 4 of the drawing in order to
describe different particular substrate configurations suitable for
implementing the present invention. These figures show
cross-sections of these substrates, passing through a contact
terminal 15 along the axis of a conductor track soldered to this
terminal. In these figures, identical or indexed reference numbers
correspond to identical or similar elements or members.
In FIG. 2, the substrate made of insulating material 7 is
metallized on its two surfaces in accordance with conductor track
or band configurations, the metallized coats being interconnected
by metallized holes such as the hole 16 passing through the
substrate. In this embodiment, the terminal 15 of the pin 5 is
soldered to a conductor track formed on the upper surface of the
substrate (from the point of view of the figure). At right angles
to the opening 6, the lower surface of the substrate is free from
any metallization. Of course, an electrical contact could also be
established in the region of the lower metallized surface of the
substrate.
FIG. 3 shows a multilayered substrate comprising several conduction
layers distributed inside the thickness of the substrate 7, the two
external surfaces of the substrate 7 themselves being metallized in
accordance with conductor track or band configurations. With this
type of substrate, the electrical contact between a terminal 15 and
a conductor track may be established in an opening 6 for example,
in the region of the upper surface of the substrate, or, on the
other hand, in the region of the lower surface of this substrate,
by means of a terminal 15' embedded in the bottom 1 of the housing
and lying flush with the surface of this bottom, making electrical
contact with a conduction band or track formed on the substrate
surface which is located opposite this bottom. The opening 6' thus
assumes the form of an entirely metallized hole. Alternatively, the
contact between a terminal 15" and a conductor track running over
the upper surface of the substrate 7 may be established inside an
entirely metallized opening 6" using the substrate surface which is
located opposite the bottom of the housing.
In FIG. 4, the substrate shown assumes the form of that used in the
abovementioned interconnection method called "dual layer TAB".
According to this interconnection method, the conduction layers or
tracks formed on the two surfaces of the substrate 7 are
interconnected by lugs 17, 17' passing through the substrate inside
openings formed for this purpose in the substrate. Such a type of
substrate is perfectly suited for incorporation of the contact
terminals 15 of the pins 5 according to the invention, passing
inside openings 6 in the said substrate.
Reference is made again to FIG. 1 which shows in broken lines a pin
5" which is also extended inside the thickness of the walls of the
bottom of the housing according to the invention by a dissipator
18, one surface of which lies flush with the bottom of the housing.
In the example of embodiment shown in FIG. 1, the component 12 is a
power component having an extended electrode soldered onto the
dissipator 18 which dissipates calories produced in the region of
this electrode by the passage of a strong current, so as to avoid
any heating of the circuit. For this purpose, the power component
12 is itself located inside a suitable opening in the substrate. A
housing comprising such a dissipator is described more completely
in French Patent Application No. 87 12241 filed on 3 September 1987
by the Applicant. It will be noted that the pins 5 with
interconnection terminals 15 of the housing according to the
invention may be associated with a pin 5" with a dissipator 18
embedded in the bottom of the housing by means of common duplicate
moulding in the material forming the housing. It is thus possible
to associate interconnection functions on the one hand and cooling
functions on the other hand inside a single housing incorporating
pins embedded in the material of the housing.
Of course, the invention is not limited to the embodiments
described and shown which have been given only by way of example.
In particular varied configurations of pins could be adopted in
particular in the portion of these pins which pass inside the
bottom 1 of the housing. Suitable overlapping of the locations
assumed by the various pins in this bottom must therefore be
ensured.
Similarly a connection terminal such as 15 may be defined in a
location such as that occupied by the connection terminal 14 of the
conductor track 10, so as to ensure a direction connection between
the terminal 15 the corresponding terminal of the component 12, by
means of a conventional soldered wire, for example.
The housing according to the invention enables the surface offered
for the interconnections between the circuit mounted on the
substrate and the input/output pins of the housing to be doubled.
The conventional interconnection plane consisting of a surface of
the substrate is in fact doubled by the plane situated inside the
thickness of the housing, where the extensions of the pins pass
towards the interconnection terminals 15.
This double arrangement avoids the problems of forming other tracks
on the surface of the substrate, when connection terminals formed
close to one edge of the substrate are to be joined together in a
conventional manner. There is also a reduction in the length of the
interconnecting conductor tracks and freeing of the substrate
surface. Furthermore, owing to the housing according to the
invention, it is possible to interconnect in a simple manner any
point of the circuit mounted on the substrate and an input/output
pin of the housing. It is obvious also that the housing according
to the invention is suitable for mass-production operations, such
as those found in motor-car electronics for example, owing to the
"automatable" nature of formation of the necessary electrical
connections between the input/output pins of the housing and the
circuit contained in this housing, by means of mechanized soldering
operations.
* * * * *